Typically, print media is fed to a printer using a mechanism comprising a pinch roller and a feed roller. Such a mechanism is illustrated in FIG. 1.
A pinch roller 1 rotatably mounted on a cylindrical pinch roller support 3 is arranged to press print media 5 against a cylindrical feed roller 7. Feeding of the media 5 is performed by driving the feed roller 7 so that it rotates about its elongate axis and conveys the media 5 by means of friction.
Feeding of the print media 5 is assisted by the pinch roller 1 which contacts the print media 5 when it is being conveyed. Accordingly, the pinch roller 1 is driven by drive means (not shown) to rotate about its elongate axis by virtue of the frictional force between the media 5 and its contacting surface.
To enable setting, loading and releasing of print media within the mechanism, the pinch roller supporter 3 can be swiveled about an axis A so as to describe an arc (indicated generally by the arrow labeled “B”). Thus, the pinch roller 1 and its supporter can be moved into a position C (the “open position”), wherein the pinch roller 1 is detached from the feed roller 7.
In a media feed mechanism such as that shown in FIG. 1, the drive means for driving the feed roller 7 are required to be controlled such that the print media is fed according to requirements, for example at a constant speed. In large format printers such requirements are of utmost importance because the printing accuracy and the speed of the printer can be directly affected by the performance of the media feed mechanism.
It is also desirable to maintain stability of the feed roller 7 when the pinch roller 1 is moved into an open position and the feed roller 7 is moved by an external force. Further, a user may move the pinch roller 1 to an open position during printing, either intentionally or unintentionally. If stability of the feed roller 7 is not maintained, it may vibrate and/or create unwanted noise.
More complicated media feed mechanisms are known which attempt to provide improved performance. However, these are generally unsuitable for lower cost or smaller printers as a direct consequence of their complexity and manufacturing requirements.
Thus, there remains a need for an improved system and/or method for feeding print media to a printer.